He is a very attractive horse. And on first look you want to love him.
But I agree with the hind end assessment of others, and the conformational slights show up in the video; while he has a lovely over track at the walk, his natural way of going does not allow him to track up, much less over track at the trot and the canter. But, he is young and has not had the training to strengthen his hind end, so his way of going has a good chance of significant improvement. However, it would not be his natural way of going so the stress might not allow him to stay sound.
The thing that I like the least is that he is not muscled the same on both sides of his hind quarters. He has less muscle on the left side. This might be fixable by several chiropractic sessions, but it should be considered at the PPE.
He does have a slight goose rump, which I do not necessarily mind. The only problem with having one is that the legs are attached in a less than ideal way. But a picture is only one moment in time. In the second picture, when his left hind is underneath him he stands sickle-hocked. The right hind is camped out, so it is hard to tell much of anything.
He has a cute jump and seems to be a really good fellow, given that he takes off long and still centers his arc. He is certainly a saleable horse, depending on the price and the goals of the buyer. I disagree with Find8 that, at 3’, he needs to “really power off the ground”. 3’ is the height for a pre-greenie. It is sad if horses have become so much less athletic that the need to power off the ground comes into play at such a low height.
He will do well in lower level dressage, but by 2nd level his natural inability to really “sit down” and overstep will begin to be a detriment.
He looks like he could make a nice 3’ horse, based on the one jump. But he will need hind end maintenence earlier, rather than later.
If the price was right, I would certainly take a chance on him.